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It's not. There's never going to be a tool that does this with black bars. The only benefit I can think of is legitimacy. Having something blurred there sugges

by rriepe 6y ago

It's not. There's never going to be a tool that does this with black bars. The only benefit I can think of is legitimacy. Having something blurred there suggests that there was actually something there.

thotsBgone 6y ago
Yeah I think blurring is more aesthetic, and until recently was seemingly just as secure. It reminds me of how people have used the Photoshop swirl tool to obscure faces, but you could just use the swirl tool in the other direction to undo the effect.
- Lammy 6y ago
  "Mr. Swirl"! https://en.wikipedia.org/wiki/Christopher_Paul_Neil#Interpol_search_and_capture https://en.wikipedia.org/wiki/Christopher_Paul_Neil#Interpol...
est31 6y ago
Black bars alone may still leak info. First, if you add black bars on your own and don't use professional redaction features of software, you might miss the OCR text layer of the PDF, or the bar might be added as a separate object entirely which means it can also be removed later on. Second, if you don't use monospace text, the width of the text you are redacting will reveal information about it. That's why monospace fonts are so commonly used in the intelligence community for example. Third, if you just add a black bar to a screenshot, there might be residual values of the text left in adjacent seemingly white portions of the image, but they might not be entirely white due to compression effects. Better you run it through a filter before publishing.
- davchana 6y ago
  Yes, in pdf, add bars, & then print it again as pdf, but as image.
  - jbverschoor 6y ago
    Even black bars all leak the face that there’s something hidden
    - davchana 6y ago
      Do you mean the typeface/font? If it is just a word we are hiding in a sentence/paragraph; it would be like fill in a blank task for reader; much more chance to guess from context. There, the leaking length will not matter.
    - davchana 6y ago
      Oh sorry, my bad, you mean fact, not face. Yes, I agree.
      - jbverschoor 6y ago
        ah. yeah fact :-)
- antegamisou 6y ago
  > First, if you add black bars on your own and don't use professional redaction features of software, you might miss the OCR text layer of the PDF, or the bar might be added as a separate object entirely which means it can also be removed later on. Looking at you, Preview on macOS.
- dragonwriter 6y ago
  > Second, if you don't use monospace text, the width of the text you are redacting will reveal information about it. If you do use monospace text, width reveals the exact redacted character count. If you don't use monospace text, it constrains the possible contents in a more complicated way, but it leaks information either way.
  - spoonjim 6y ago
    It leaks much less information when monospaced, although that information is easier to retrieve. Anyone can just visually inspect and see exactly how many monospaced characters were removed, but someone with the right tools and skills can narrow down the potential characters quite a bit if it's a short piece of non monospaced text.
- spoonjim 6y ago
  This is why the real professionals use the same mechanism they always have: cut the offending text out of the paper with an x-Acto knife and make a photocopy.
  - deleted 6y ago
    [deleted]
  - Scoundreller 6y ago
    Also helps prevent any issues related to double sided printing and bleedthrough.
xorcist 6y ago
There is still a risk to leak the length of the password. If the font is known and the size of the rendered text can be inferred that would limit the search space considerably.
- davchana 6y ago
  Personal Snippet, if I want to hide/cross something I wrote on paper, I usually change letters to something else, like u to g, i to d, nothing preplanned, whatever comes in mind, before I cross line the text in forward slashes, backword slashes, & in horizontal lines.
  - bonoboTP 6y ago
    I thought I was the only one! Such a great trick. Just write random letters or even random sentences over your handwriting perhaps 2 or 3 times, then heavily cross it out and it's impossible to recover.
  - KineticLensman 6y ago
    I sometimes write down on paper my banking passphrase (from which the bank makes me select letters at specific position). Afterwards I overwrite it a few times with the alphabet and a few numbers and other random letters. It's totally unreadable.
- nickjj 6y ago
  > There is still a risk to leak the length of the password. If the font is known and the size of the rendered text can be inferred that would limit the search space considerably. I do a lot of screencast videos and what I typically do is put a black rectangle well past the point where my secret text really ends. If my secret is: mysupersecretpassword You might end up seeing a black bar of: |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||| What I'm most afraid of is accidentally having literally 1 frame of video where the bar isn't present. This is super easy to do if you're just scrolling through a timeline while editing. You need to really dive in and move frame by frame to ensure you get everything. I usually extend it a few frames in either direction just to be safe too.

by rriepe 6y ago

thotsBgone 6y ago

Yeah I think blurring is more aesthetic, and until recently was seemingly just as secure. It reminds me of how people have used the Photoshop swirl tool to obscure faces, but you could just use the swirl tool in the other direction to undo the effect.

Lammy 6y ago
"Mr. Swirl"! https://en.wikipedia.org/wiki/Christopher_Paul_Neil#Interpol_search_and_capture https://en.wikipedia.org/wiki/Christopher_Paul_Neil#Interpol...

est31 6y ago

Black bars alone may still leak info. First, if you add black bars on your own and don't use professional redaction features of software, you might miss the OCR text layer of the PDF, or the bar might be added as a separate object entirely which means it can also be removed later on. Second, if you don't use monospace text, the width of the text you are redacting will reveal information about it. That's why monospace fonts are so commonly used in the intelligence community for example. Third, if you just add a black bar to a screenshot, there might be residual values of the text left in adjacent seemingly white portions of the image, but they might not be entirely white due to compression effects. Better you run it through a filter before publishing.

davchana 6y ago
Yes, in pdf, add bars, & then print it again as pdf, but as image.
- jbverschoor 6y ago
  Even black bars all leak the face that there’s something hidden
  - davchana 6y ago
    Do you mean the typeface/font? If it is just a word we are hiding in a sentence/paragraph; it would be like fill in a blank task for reader; much more chance to guess from context. There, the leaking length will not matter.
  - davchana 6y ago
    Oh sorry, my bad, you mean fact, not face. Yes, I agree.
    - jbverschoor 6y ago
      ah. yeah fact :-)
antegamisou 6y ago
> First, if you add black bars on your own and don't use professional redaction features of software, you might miss the OCR text layer of the PDF, or the bar might be added as a separate object entirely which means it can also be removed later on. Looking at you, Preview on macOS.
dragonwriter 6y ago
> Second, if you don't use monospace text, the width of the text you are redacting will reveal information about it. If you do use monospace text, width reveals the exact redacted character count. If you don't use monospace text, it constrains the possible contents in a more complicated way, but it leaks information either way.
- spoonjim 6y ago
  It leaks much less information when monospaced, although that information is easier to retrieve. Anyone can just visually inspect and see exactly how many monospaced characters were removed, but someone with the right tools and skills can narrow down the potential characters quite a bit if it's a short piece of non monospaced text.
spoonjim 6y ago
This is why the real professionals use the same mechanism they always have: cut the offending text out of the paper with an x-Acto knife and make a photocopy.
- deleted 6y ago
  [deleted]
- Scoundreller 6y ago
  Also helps prevent any issues related to double sided printing and bleedthrough.

xorcist 6y ago

There is still a risk to leak the length of the password. If the font is known and the size of the rendered text can be inferred that would limit the search space considerably.

davchana 6y ago
Personal Snippet, if I want to hide/cross something I wrote on paper, I usually change letters to something else, like u to g, i to d, nothing preplanned, whatever comes in mind, before I cross line the text in forward slashes, backword slashes, & in horizontal lines.
- bonoboTP 6y ago
  I thought I was the only one! Such a great trick. Just write random letters or even random sentences over your handwriting perhaps 2 or 3 times, then heavily cross it out and it's impossible to recover.
- KineticLensman 6y ago
  I sometimes write down on paper my banking passphrase (from which the bank makes me select letters at specific position). Afterwards I overwrite it a few times with the alphabet and a few numbers and other random letters. It's totally unreadable.
nickjj 6y ago
> There is still a risk to leak the length of the password. If the font is known and the size of the rendered text can be inferred that would limit the search space considerably. I do a lot of screencast videos and what I typically do is put a black rectangle well past the point where my secret text really ends. If my secret is: mysupersecretpassword You might end up seeing a black bar of: |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||| What I'm most afraid of is accidentally having literally 1 frame of video where the bar isn't present. This is super easy to do if you're just scrolling through a timeline while editing. You need to really dive in and move frame by frame to ensure you get everything. I usually extend it a few frames in either direction just to be safe too.